Recent advancements in digital advertising technologies combined with the reduction in costs of these technologies have led to increasing pressure on governments to approve their installation adjacent to roads. These signs typically use light-emitting diode (LED) technologies with the capability of displaying dynamic messages with high luminance levels. They are specifically designed to attract maximum driver attention and subsequently create maximum driver distraction. Although the effect of roadside advertisements on driver distraction and road safety has been researched since the 1930s, digital advertising is relatively new and its effect on road safety is still inadequately understood. However, jurisdictions must be prepared to evaluate requests for these advertisements and develop policies and regulations for their control with an understanding about their potential impact on road safety. This paper summarizes the findings from a literature review on the road safety impacts of digital and projected advertising displays (DPADs). Specifically, it identifies challenges for regulating DPADs and assessing their impact on road safety, discusses issues concerning DPAD policy and regulation, and reveals considerations for DPAD policy and regulation. Current research is unable to conclusively determine the road safety impact of DPADs; consequently road authorities have difficulty accepting or rejecting DPAD applications on the basis of safety and advertisers have difficulty demonstrating that DPADs do not negatively impact safety. Despite the lack of conclusive evidence, the literature provides sufficient information to guide policy and regulatory direction concerning DPADs.
